Rust inhibiting distillate petroleum hydrocarbon fuel compositions

ABSTRACT

DISTILLATE PETROLEUM HYDROCARBON FUELS SUCH AS MOTOR GASOLINE, AVIATION GASOLINE, KEROSENE, AND FUEL OILS ARE IMPROVED AS TO THEIR RUST INHIBITING AND RUST PREVENTING CHARACTERISTICS BY INCORPORATING THEREINTO EFFECTIVE BUT SMALL AMOUNTS OF AT LEAST ONE ORGANIC SULFOXIDE HAVING THE FORMULA: R-S(=O)-R1 WHEREIN RS A RADICAL SELECTED FROM THE GROUP CONSISTING OF -CNH2NCOOH; -CNH2NOH; -CNH2NOCNH2N+1;   -CNH2NCOCNH2N+1; -CNH2NOOCCNH2N+1;   -CNH2NCOOCNH2N+1;   -CNH2NOOCCH(CH2COOH)CNH2N-1;   -CNH2NOOCH(CH2COOCNH2N-)CNH2N-1;   AND R1 IS A RADICAL SELECTED FORM THE GROUP CONSISTING OF -CNH2N+1; -CNH2NC6H5; -CNH2NC6H4CNH2N+ $; AND ANY OF THE RADICALS LISTED FOR R, N BEING A WHOLE NUMBER. AT LEAST ONE OF R AND R1 HAS A TOTAL OF FROM 1O TO 250 CARBON ATOMS. THE AMOUNTS OF THE SULFOXIDES EMPLOYED RANGE BETWEEN ABOUT 0.1 AND ABOUT 100 POUNDS PER THOUSAND BARRELS (42 GALLONS PER BARREL) OF FUEL.

United States Patent Olhce 3,591,354 Patented July 6, 1971 3,591,354 RUST INHIBITIN G DISTILLATE PETROLEUM HYDROCARBON FUEL COMPOSITIONS Roland A. Bouifard, Union, N.J., assignor to Esso Research and Engineering Company No Drawing. Filed Dec. 27, 1967, Ser. No. 693,741

Int. C1. C! 1/24 US, C]. 4470 6 Claims ABSTRACT OF THE DISCLOSURE Distillate petroleum hydrocarbon fuels such as motor gasoline, aviation gasoline, kerosene, and fuel oils are improved as to their rust inhibiting and rust preventing characteristics by incorporating thereinto effective but small amounts of at least one organic sulfoxide having the formula:

wherein Rs a radical selected from the group consisting of -C,,H ,,COOH; -C H OH; C H OC H DESCRIPTION OF THE INVENTION The present invention is concerned with novel compositions involving distillate petroleum hydrocarbon fuels which contain rust inhibiting amounts of at least one fuelsoluble organic sulfoxide. These organic sulfoxides contain, as a minimum, at least 11 carbon atoms per molecule for it has been found that organic sulfoxides containing a lesser number of carbon atoms are not sufficiently fuelsoluble to impart effective rust inhibiting characteristics to the hydrocarbon fuels to which they are added.

Commercially available distillate hydrocarbon fuel compositions such as motor gasoline, aviation gasoline, jet fuels, kerosene, and fuel oils ordinarily contain small amounts of water or Water vapor or they accumulate, during transport and/or storage, such small amounts of water. Generally speaking, these fuel compositions are stored in steel or iron tanks and are conducted or transported through pipes composed of steel or iron. Addi tionally, the storage tanks, feeder lines, carbureting and atomizing devices through which and into which such compositions are conducted or passed are likewise com posed of iron or steel in large measure. There is, therefore, a considerable tendency, in continued usage over prolonged periods of time, for various of these parts contacting such fuels to rust or otherwise corrode by reason of the continued contacting of the iron or steel surfaces with moisture or water. In the past, considerable effort has been made to overcome this rusting tendency and to reduce the amount of rust and thus of corrosion incurred, so that the valves, pumps, atomizer devices, tanks and passage lines are subjected to a minimum of rusting and its incident corrosion effects. It is virtually impossible to entirely prevent the occurrence of water in intimate association with these fuels at all times and under all circumstances and so for the most part efforts have been expended in the direction of incorporating certain types of additives to such hydrocarbon fuels for the purpose of counteracting, inhibiting and minimizing the deleterious action of water and water vapor on the various metal parts which contact such fuels. To some extent also and under certain atmospheric conditions, the water present in association with such fuels tends to solidify and the resultant ice causes the clogging or plugging of orifices, filter screens, pipes and lines of restricted cross-sectional area, i.e., fuel pumps and the like.

The present invention is directed to the compounding of moisture-containing hydrocarbon fuel compositions containing a minor but effective amount of certain types of organic sulfoxides so that it is possible when these sulfoxides are present in the fuel compositions to eliminate, in large part, the rusting tendencies of the fuels and at the same time to further minimize the icing tendencies of such fuels. The improvement of these fuels from the standpoint of rusting characteristics and icing characteristics is highly desirable for their use and their commercial acceptance is dependent upon their trouble-free operation in the systems in which they are stored, conveyed and burned.

The lower molecular weight organic sulfoxides have been employed in the past in hydrocarbon fuels for the purpose of minimizing the icing tendencies of such watercontaining fuels. Thus, for example, U.S. Pat. No. 2,932,- 5 60, issued to Mills, Apr. 12, 1960, discloses the use of C C dialkyl sulfoxides in petroleum fuels for the purpose of suppressing carburetor icing. Similarly, British Pat. No. 807,010 discloses the use of organic sulfoxides of the type;

wherein R and R are organic radicals containing not more than 8 carbon atoms each, in petroleum fuels containing water for the purpose of controlling the troublesome icing problem. In these cases, however, the organic sulfoxides employed while performing the function of inhibiting ice formation in the petroleum fuels are of such low molecular weight that they do not effectively or beneficially control the tendency of such water-containing fuels to rust the intricate parts of atomizers, fuel pumps, carburetors, fuel injectors and the like.

It has now been discovered that if organic sulfoxides containing an R and R having a minimum of 11 carbon atoms per molecule (either R or R having at least 10 carbon atoms) and which are fuel-soluble are employed, in minor amounts, in such water-containing fuel composition, the resultant so-treated fuel compositions possess outstanding rust inhibiting and rust minimizing properties. Generally speaking, the organic sulfoxides employed are not new compounds and generally speaking they are most simply derived from the corresponding organic thioether or organic sulfides through the simple expedient of subjecting such materials to controlled oxidation.

The conventional organic sulfides of the higher molecular weights which are used in compounding the novel fuel compositions of the present invention are prepared according to procedures well-known in the art. The thioethers or sulfides may be treated with air, nitrogen oxides, hydrogen peroxide, benzoyl peroxide, tor n-dibutyl peroxide, lauryl peroxide, nitric acid or the like, and, although some sulfones may form simultaneously with the formation of the sulfoxides, generally, they are not present in the final reacted mixture to a sufficient extent to warrant their removal before the use of the sulfoxides in the water-containing fuel compositions.

Numerous other methods, which incidentally yield sulfoxides of higher purity, i.e., with less sulfone formation, are those set forth, for example, in US. Pat. No. 3,288,- 860, issued Nov. 29, 1966. Typical reactions that may be employed are the following: di-lower alkyl sulfoxides such as dimethyl sulfoxide or methyl, alkyl sulfoxide with chains up to 22 carbon atoms, may be reacted with strong bases such as caustic soda or potassium hydroxide, an alkali metal hydride or an alkali metal amide followed by a reaction of this intermediate with an alkyl halide, such as bromide or chloride, to produce the dialkyl sulfoxide or the intermediate from the initial reaction may be reacted with an epi-oxide or a hydrin to produce the corresponding gamma hydroxy alkyl sulfoxide. Similarly, a carboxyl acid ester or di-ester of a dicarboxyl acid may be reacted with the alkali metal intermediate to produce the corresponding keto derivative of the dialkyl sulfoxide. As before mentioned, however, the simplest method is to effect a controlled oxidation of the corresponding organic sulfide or thioether, for example, such materials as alkyl substituted mercapto, lower fatty acids or thio diethanol may be subjected to oxidation to produce the corresponding sulfoxides. Chlorhydrins may be used in place of the epoxides. In any event, the procedures for producing the H sulfoxides are well-known and are conventional as are the particular high molecular weight sulfoxides employed as rust inhibiting additives for the water-containing fuel compositions. Most of the starting materials, i.e., the sulfides and the thioethers, are available commercially on the open market and the use of a 30% hydrogen peroxide solution on these commercially available sulfides and thioethers results in the formation of the corresponding sulfoxides. The important consideration so far as the success of any particular sulfoxide is concerned is that it must contain at least 11 carbon atoms per molecule, for those materials which contain a lesser number of carbon atoms do not possess satisfactory fuel solubility to perform the rust inhibiting function to any advantageous degree. Not only must the sulfoxides contain a minimum of 11 carbon atoms but additionally in the formula:

R-Q-R one of the Rs must be an organic radical containing at least carbon atoms. The number of carbon atoms in any one R or R group may range as high as 250 but it has been found through experimentation that at least one of the two Rs must contain a minimum of 10 carbon atoms per radical.

In the above formula, and as specific examples of the types of sulfoxides which may be employed in the instant invention, the R radical may be any one of the following:

polyisobutenyl CH COO CH CH polyisobutenyl CH CO 0 CH CHz CHZCOOH CHzCOOCHzCHZ Additionally, R may be CH C H i-C H n-C H i h 4 9: s u CGHIS: a 17, a 19 as Well as any of the radicals set forth for R.

Preferably the sulfoxides, while they must contain a minimum of 11 carbon atoms per molecule in order to be effective, generally have more than 15 carbon atoms per molecule. Additionally, and generally speaking, the more polar groups contained in the sulfoxide molecule, the greater number of carbon atoms per R or R group that is necessary to obtain sufficient fuel solubility and conversely the fewer polar groups contained in any particular sulfoxide molecule, the lesser number of carbon atoms in R or R are required to achieve the desired fuel solubility.

4 Typical preferred sulfoxides that may be employed as additives for imparting effective rust inhibiting character istics to hydrocarbon fuels are the following:

g; II liicwsonlcmcoon, H3C o1.t2soH2coolr ll polyisobutenyl (850M.W.) ClHCOOCH2CH2S cH2oHfloH C H20 0 OH OHO ll IIIHCHCOOCHZSCIIZOOC 0151131 I ll IIUCZOCOO CH S CHZOH, HuC COOCH S CH3 Boiling range F. Motor gasoline 70 to 450 Aviation gasoline to 330 Jet fuel to 500 Kerosene 330 to 520 No. 2 heating oil 325 to 645 Such fuels are generally composed of mixtures of various types of hydrocarbons principally normally paraffins, isoparafiins, naphthenes, olefins and aromatics. As between any particular type of fuel and another and even as between different types of fuels employed for the same purpose, the relative amounts or ratios of one type of constituent to the other type of constituent present will vary over considerable ranges not only because of the type of crude oil from which the particular fuel was derived but also because of blending operations within the refinery and/or because of the various types of refinery treatments to which the fractions of the crude oil are subjected within the refinery. Thus, for example, hydrocracking, catalytic cracking, hydroalkylation, hydroforming, and the like are conventionally employed at various times and either singly or in combination to achieve certain desired final burning characteristics and physical characteristics in particular fuels. The addition of the higher molecular weight organic sulfoxides hereindescribed imparts to any of these fuels outstanding rust inhibiting properties and this fact seems to be true regardless of any particular percentage of one constituent or ratio of percentages of constituents found in the particular fuel by reason of its particular method of manufacture or by reason of the particular crude employed and from which the fuel is ultimately derived.

Other conventional additives are employed in these fuels in accordance with commercial practice and dependent upon the particular use to which the fuel is to be put. For example, aviation fuels and motor fuels commonly will contain between about 0.5 and about 7.0 cc. per gallon of conventional anti-knock agents such as tetraethyl lead, tetramethyl lead, dimethyl, diethyl lead or similar alkyl lead anti-knock compounds. Other materials conventionally employed are corrosion inhibitors such as polymerized linoleic acid, N,Cdialkyl derivatives of the imidazolines, cold flow improvers particularly in fuel oils, such as the ethylene-vinyl acetate copolymers, antioxidants, such as phenols and amino phenols, antifoulants, such as tricresyl phosphate, combustion modifiers, such as alkyl boronic acids, alkyl phosphates and alkyl phosphites, octane appreciators, such as tertiary butyl acetate, auxiliary lead scavengers, such as ethylene dichloride or dibromide, tri betachloroethyl phosphate and auxiliary anti-icing agents, such as isopropanol, hexylene glycol, or the lower molecular weight dialkyl sulfoxides mentioned in British Pat. No. 807,010 and U.S. Pat. No. 2,932,560. Additional oil-soluble dispersants and/or detergents for engine cleanliness such as those disclosed in U.S. Pat. No. 3,223,495 may also be employed.

The amount of the higher molecular weight organic sulfoxides may vary between about 0.1 and 100 pounds per thousand barrels (42 gallon per barrel) of fuel compounded. Preferably, however, and from a practical standpoint, eflicacious results are achieved using between about 2 and about pounds of higher molecular weight organic sulfoxides per thousand barrels of fuel.

Quite often it is advantageous to employ a solvent oil that is mutual solvent for the fuel and the sulfoxide in order to effectively introduce the organic sulfoxides into the fuel and to make them readily soluble in the fuel. This is particularly true if the carbon atoms in the R or R group are relatively few and the number of polar groups in the sulfoxide molecule is relatively large. Although the invention does not depend upon the use of such organic solvents, from a practical standpoint, it is often expedient to employ suflicient amounts of organic solvents to insure complete solubility of the particular sulfoxides or mixtures of sulfoxides being added to the fuel. Suitable solvents which may be employed for this purpose may be mixtures of hydrocarbons, such as heavy aromatic naphthas, mixtures of alcohol and xylene, benzene, toluene, the polyhydric alcohols, such as ethylene glycol or propylene glycol, ketones, such as acetone and methylethyl ketone and ethers, such as diethyl ether, di-isopropyl ether and the methyl or ethyl ethers of ethylene glycol or propylene glycol.

The following examples are given by way of illustration. It is not intended that the invention be limited thereto.

EXAMPLES A base gasoline was prepared having the following inspection.

Using the gasolines described above, blends were prepared with various sulfoxides and duplicate tests were run on each blend. These tests were designed to measure the amount of rusting that took place and were a modification of ASTM Test D-665. In this test, 350 cc. of the gasoline blend above described, with and without additives, held at a temperature of 77 F., is stirred with a polished soft steel spindle. After 10 minutes of stirring for the purpose of conditioning the spindle, 50 cc. of the gasoline blend is removed from the gasoline and 30 cc. of water is added to the gasoline. Stirring is continued for 1 hour while maintaining a 77 F. temperature. The steel spindle is then removed from the mixture of gasoline and water and inspected for rust spots. Rust that does not exceed 5% of the area of the spindle is considered as a satisfactory showing of lack of formation of rust. In the following table, unless otherwise shown,

the figures for this rust test are given in percentage of the total area covered or coated with rust.

TABLE I Concentration of additive,

lbs. per Perl,000 cent Run Additive barrels rust l None 2.. Di-butyl sulfoxide 5. 0 50 3-. Di-octyl sulfoxide 2. 5 50 t 4.-.... C11 H23COOCHZCHZS"CH2CH2OH 2. 5 20-30 I! 5.. RCOOCHzCHzSCHzCH2OH 6 1 ll 6..-. RrSCHzCOOH 5 0 7 Same as above 2. 5

8 R!I-SCH2COOH 5 0 9"..- Sameasabove 2.5 0

1 5-6 spots.

R in Run 5 is polyisobutenyl succinic acid ester having a number average molecular Weight of 985.

R in Runs 6 and 7 is a mixed C -C alkyl fraction.

R in Runs 8 and 9 is a mixed C -C alkyl fraction.

The alkyls of R and R were present in S-mixed alkyl thioglycollic acids purchased on the open market. These were oxidized to yield the corresponding sulfoxides. The starting materials were believed to have been prepared by reacting thioglycollic acid with the corresponding mixed alpha monoolefins.

It will be seen from a study of the above data that substantial rusting occurred when no additive was employed in the base gasoline as shown in Run 1, and when alkyl sulfoxides having less than 10 carbon atoms in at least one radical attached to the 0 II S group were used as evident 'by the data in Runs 2 and 3 rusting was prevalent. In those runs wherein at least one radical attached to the 0 II S group contained at least 10 carbon atoms, a marked reduction, and, in most cases, a complete reduction to 0% rust was obtained when even as small an amount as 2.5 pounds of additive per thousand barrels of gasoline were employed.

Additionally, it is evident from the above data that using a sulfoxide containing a functional group (OH, COOH, COOR) beta to the sulfoxide radical improves the antirust property and its effectiveness if the other radical attached to the sulfur atom contains a radical having at least 10 carbon atoms.

Having now thus fully described and illustrated the invention, what is desired to be secured by Letters Patent is:

1. A distillate hydrocarbon fuel boiling in the range comprising gasoline, jet fuel, kerosene, and fuel oil, and subject to contact with moisture, which has been improved with respect to rust inhibition by incorporating therein a rust-inhibiting amount of a fuel-soluble organic sulfoxide having the formula:

RLl-R1 wherein R is a radical selected from the group consisting Of 'C H2 OH; -C H OC I-I n 2n 11 2n+1; n 2n n 2n+-1 -C H OOCCH(CH COOC H -)C H and R is a radical selected from the group consisting of -C,,H C I-l C I-l -C H C H C l-l and any of the radicals listed for R, n being a whole number, at least one of R and R having a total of from 10 to 250 carbon atoms.

2. Fuels defined by claim 1 wherein the organic sulfoxide is present in an amount of between about 0.1 and about 100 pounds per thousand barrels of fuel.

3. Fuels defined by claim 2 wherein the organic sulfoxide is wherein R is a mixture of alkyl radicals ranging between about C and about C HzaCuCOOCH CIIg-fi-CH CEhOH 6. A moisture-containing gasoline containing a rust inhibiting amount of a gasoline soluble organic sulfoxide having the formula:

0 Polyisobutenyl-CHCOO OHZOHQS CHzCHzOH CHZCOOH References Cited UNITED STATES PATENTS 8/1960 Sullivan 252-4195 8/1960 Flanagan 4476 DANIEL E. WYMAN, Primary Examiner Y. H. SMITH, Assistant Examiner US. Cl. X.R. 

